1. Technical Field
The invention relates to a method and apparatus for providing directory assistance, at least partially automatically, to telephone subscribers.
2. Background Art
In known telephone systems, a telephone subscriber requiring directory assistance will dial a predetermined telephone number. In North America, the number will typically be 411 or 555 1212. When a customer makes such a directory assistance call, the switch routes the call to the first available Directory Assistance (DA) operator. When the call arrives at the operator's position, an initial search screen at the operator's terminal will be updated with information supplied by the switch, Directory Assistance Software (DAS), and the Operator Position Controller (TPC). The switch supplies the calling number, the DAS supplies the default locality and zone, and the TPC supplies the default language indicator. While the initial search screen is being updated, the switch will connect the subscriber to the operator.
When the operator hears the "customer-connected" tone, the operator will proceed to complete the call. The operator will prompt for locality and listing name before searching the database. When a unique listing name is found, the operator will release the customer to the Audio Response Unit (ARU), which will play the number to the subscriber.
Telephone companies handle billions of directory assistance calls per year, so it is desirable to reduce labour costs by minimizing the time for which a directory assistance operator is involved. As described in U.S. Pat. No. 5,014,303 (Velius) issued May 7, 1991, the entire disclosure of which is incorporated herein by reference, a reduction can be achieved by directing each directory assistance call initially to one of a plurality of speech processing systems which would elicit the initial directory assistance request from the subscriber. The speech processing system would compress the subscriber's spoken request and store it until an operator position became available, whereupon the speech processing system would replay the request to the operator. The compression would allow the request to be replayed to the operator in less time than the subscriber took to utter it. Velius mentions that automatic speech recognition also could be employed to reduce the operator work time. In a paper entitled "Multiple-Level Evaluation of Speech Recognition Systems", the entire disclosure of which is incorporated herein by reference, John F. Pitrelli et al disclose a partially automated directory assistance system in which speech recognition is used to extract a target word, for example a locality name, from a longer utterance. The system strips off everything around the target word so that only the target word is played back to the operator. The operator initiates further action.
U.S. Pat. No. 4,797,910 (Daudelin) issued Jan. 10, 1989, the entire disclosure of which is incorporated herein by reference, discloses a method and apparatus in which operator involvement is reduced by means of a speech recognition system which recognizes spoken commands to determine the class of call and hence the operator to which it should be directed. The savings to be achieved by use of Daudelin's speech recognition system are relatively limited, however, since it is not capable of recognizing anything more than a few commands, such as "collect", "calling card", "operator", and so on.
These known systems can reduce the time spent by a directory assistance operator in dealing with a directory assistance call, but only to a very limited extent.